Overall objectives of the project: l. To develop an animal model for EB virus in primates. 2. To study mechanisms controlling expression of the viral genome in EBV converted lymphoblastoid cell lines. (3) To study aspects of the pathogenesis of EBV infections in man. Goals for the current year: 1. To continue studies of malignant lymphoma in marmosets after inoculation of EBV. 2. To determine whether there are biologic, antigenic, or structural differences among strains of EBV. 3. To investigate the effects of immunosuppressive therapy on EBV infections in man.